package com.lyz.dataStructure.考研上机编程题;/**
 * @Author:759057893@qq.com Lyz
 * @Date: ${Date} 0:35
 * @Description:
 **/

import java.util.Scanner;

/**
 *@Author:759057893@qq.com Lyz
 *@Date: 2019/9/18 0:35
 *@Description:
 **/
public class 输出n的阶乘 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
       long n = sc.nextLong();
        System.out.println(returnNum(n));
    }
    public static long returnNum(long n){
        if(n<2) return 1;
        return n*returnNum(n-1);
    }
}
